1. Field of Invention
The present invention relates to processes of enlarging, reducing, and modifying bitmap fonts.
2. Description of Related Art
Bitmap fonts are used for displaying characters and so on in devices such as cellular phones or Personal Digital Assistant (PDAs). Bitmap fonts display characters or symbols, by means of previously prepared pixel array patterns. In contrast to outline fonts, which display characters or symbols, by a set of vector data, bitmap fonts have a small data volume per character, owing to their simple pixel array patterns. For this reason, bitmap fonts are used in cellular phones or PDAs where the number of pixels of the display area is relatively small.
In the case of displaying characters or symbols on a display device, it is sometimes necessary to enlarge or reduce the characters. In bitmap fonts used for cellular phones, PDAs, and the like, the size of the characters is small and there are also many cases where characters are displayed with a thickness of one pixel. In that case, when enlarging bitmap fonts by the method of carrying out simple coordinate transformation based on the aspect ratio between sizes of an original character and an enlarged character thereof, there may be unnatural-looking portions, in terms of thickness, in the enlarged character. Further, when reducing such small bitmap fonts by the above-described simple coordinate transformation, there might be a line having an unnatural thickness due to distortion in the reduced character, or a case where the reduced character does not correspond with the original character owing to unsuitable connection between portions thereof.
Further, in case of displaying characters or symbols on a display device, there are instances where it is required to modify the character or the symbol. For example, it may be necessary to display a font that has the equal standard aspect ratio by modifying the widthwise font and lengthwise. This requirement may depend on the user's preference that lengthwise or widthwise modified characters can be easily seen, and so on. That requirement may occur from mainly the processing on a display device, depending on the configuration of the display area of the display device or the formation of the image to be displayed. For instance, since lengthwise displayed characters can easily be seen on a lengthwise-type display area or since images are displayed together with composition in the display area, the configuration of the characters may be modified and displayed in relation to the display size or the display position of the image.